1. Field of the Invention
The present invention relates to a display device, and more particularly, to a plasma display and a manufacturing method thereof.
2. Related Art
A prior art plasma display includes two glass substrates provided opposing one another (hereinafter referred to as the front substrate and the rear substrate). A plurality of electrodes are formed over an inside surface of the front substrate, and a dielectric layer, which includes a protection layer made of a compound such as MgO, is formed covering the electrodes. Further, a plurality of electrodes is formed on an inside surface of the rear substrate. The electrodes are provided perpendicular to the electrodes formed on the front substrate. In order to form discharge cells, which are spaces where gas discharge is performed, a plurality of barrier ribs are formed on the rear substrate. That is, the barrier ribs are formed to both sides of each of the electrodes and parallel to the same. Dielectric layers with a high reflexibility are formed covering the electrodes and on surfaces of the barrier ribs in each of the discharge cells. Also, R (red),G (green),B (blue) phosphor layers are formed over the dielectric layers in each of the discharge cells.
The substrates structured as in the above are sealed in a state where a discharge gas such as Ne or He is provided in the discharge cells. A voltage is selectively provided to terminals connected to the electrodes protruding from the sealed substrates, thereby generating a discharge between the electrodes in the discharge cells. As a result of the discharge, excitation light emitted from the phosphor layers is displayed externally.
The following gives an example of how the rear substrate in such a plasma display may be manufactured.
First, a plurality of electrodes are patterned and formed by printing, etc., then sintered and secured on an original substrate glass. Next, a dielectric layer having a high reflexibility is deposited and sintered on the original substrate on which the electrodes are formed. A barrier rib material is then deposited on the original substrate glass to cover the electrodes and the dielectric layer. Next, after patterning using a photoresist such as a dry film resist (DFR), the barrier rib material except where the photoresist is formed is removed by, for example, a sand blast process.
That is, glass beads having a particle diameter of approximately 20-30 μm (micrometers) or an abrasive such as calcium carbonate is sprayed through a nozzle to remove portions of the barrier rib material not covered by the patterned photoresist. Accordingly, the lattice wall material under the photoresist pattern is left remaining to form barrier ribs. Although portions of the dielectric layer come to be exposed during the sand blast process, since the dielectric layer is hardened by sintering such that it is made harder than the barrier rib material, removal by the sand blast process stops at the surface of the dielectric layer. Next, sintering is performed to complete the fabrication of the barrier ribs and thereby form discharge cells.
Following the above processes, phosphor pixels are formed using a screen-printing process in each of the discharge cells, which are separated by the barrier ribs. The screen-printing process is a process by which a paste mixed with phosphor material is provided in the discharge cells, then dried using printing techniques performed by interposing a screen.
The barrier rib is a material that minimizes by as much as possible the amount of organic material used as a binder for maintaining the shape of the barrier ribs following drying such that removal by sand blasting is easy. The dielectric layer is made difficult to remove by sand blasting as a result of the sintering the dielectric layer as described above. However, with the application of heat to glass (original substrate glass in this case) during sintering, the glass undergoes deformation (e.g., contracts). Accordingly, it is preferable to reduce the sintering temperature or reduce the number of sintering operations to avoid such deformation.
Japanese Laid-Open Patent No. Heisei 8-212918 for Manufacture of Plasma Display Panel by Hiroyuki et al. discloses a method in which another substrate glass is directly etched to form barrier ribs. With this method, a sintering process need not be performed to form the barrier ribs as in the method described above, thereby avoiding the problem of glass deformation.
With this method, electrodes and dielectric layers provided between the barrier ribs are formed using the conventional screen-printing process after each lattice wall is formed. However, since a height of the barrier ribs is 150 μm (micrometers) or more, it becomes an involved process to provide the materials to the bottom of and between the barrier ribs, thereby making application of the screen-printing process difficult.